Extracting energy from water has been done for ages with watermills and the like. Hydroelectric power plants are well known and widespread today and typically use a turbine generator which extracts energy from river water accumulated by a dam. However, the field of stream flow hydroelectric generators is relatively recent.
Stream flow hydroelectric generators are of the type which are typically to be used to extract energy from natural water currents. Stream flow hydroelectric generators have been designed to extract energy from the currents generated by the tides, or from rivers for instance.
There have been two main approaches to stream flow hydroelectric generators. The first approach is to suspend watermills at mid-depth from above. The second approach concerns providing the watermills on a sinking base which is anchored to the ground.
An example of an anchored hydroelectric generator is provided in the international patent application published under no. WO 2009/081162 and also published as United States application publication US 2009/0162144. Such hydroelectric generators have been satisfactory to a certain degree, but have some limitations at least with respect to certain applications.
One of these limitations is linked to the relative complexity of the method of installation. Installation is described in this publication as requiring the combined action of both a floating crane and a workboat. Such equipments are typically quite expensive, not always accessible, and have limited versatility, especially concerning a floating crane.
Also, on anchored systems, maintenance is an issue. Either it requires retrieval of the system, the inconveniences of which will appear from the description above, or it requires the intervention of skilled divers, which is also undesirable given the costs and potential safety considerations.
It will thus be understood that there remained room for improvement.